python-model: Support importing multiple versions

python/revng/model/_common/base.py

@@ -10,12 +10,29 @@ from pydantic.main import ModelMetaclass
 
 def get_monkey_patching_metaclass(
     substitutions: Dict[str, type],
+    register_global_yaml_helpers=False,
 ):
     """Returns a metaclass which transparently substitutes some types with others. This way pydantic uses the substitute
     types when creating the validators for its types, without the need to modify the autogenerated classes.
     """
 
     class MonkeyPatchingMetaClass(ModelMetaclass):
+        class YamlLoader(yaml.Loader):
+            pass
+
+        class YamlDumper(yaml.Dumper):
+            def increase_indent(self, flow=False, indentless=False):
+                """Improves indentation"""
+                return super(MonkeyPatchingMetaClass.YamlDumper, self).increase_indent(flow, False)
+
+            def analyze_scalar(self, scalar):
+                """Ensures literals starting with ? are quoted to make LLVM YAML parser happy"""
+                analysis = super(MonkeyPatchingMetaClass.YamlDumper, self).analyze_scalar(scalar)
+                if isinstance(analysis.scalar, str) and analysis.scalar.startswith("?"):
+                    analysis.allow_flow_plain = False
+                    analysis.allow_block_plain = False
+                return analysis
+
         @staticmethod
         def __new__(mcs, clsname, bases, namespace):
             substitution = substitutions.get(clsname)
@@ -43,17 +60,25 @@ def get_monkey_patching_metaclass(
                         {k: v for k, v in instance._iter(exclude_none=True)},
                     )
 
-            yaml.add_representer(
+            mcs.YamlDumper.add_representer(
                 created_class,
                 yaml_representer,
             )
+            if register_global_yaml_helpers:
+                yaml.add_representer(
+                    created_class,
+                    yaml_representer,
+                )
 
             def yaml_constructor(loader, node):
                 mapping = loader.construct_mapping(node, deep=True)
                 return created_class(**mapping)
 
             tag = f"!{clsname}"
-            yaml.add_constructor(tag, yaml_constructor)
+
+            mcs.YamlLoader.add_constructor(tag, yaml_constructor)
+            if register_global_yaml_helpers:
+                yaml.add_constructor(tag, yaml_constructor)
 
             return created_class
 
@@ -62,10 +87,12 @@ def get_monkey_patching_metaclass(
 
 def get_monkey_patching_base_class(
     substitutions: Dict[str, type],
+    register_global_yaml_helpers=False,
 ):
     """Returns a base class which transparently substitutes some model types with others"""
     MonkeyPatchingMetaClass = get_monkey_patching_metaclass(
         substitutions,
+        register_global_yaml_helpers=register_global_yaml_helpers,
     )
 
     class MonkeyPatchingBaseClass(BaseModel, metaclass=MonkeyPatchingMetaClass):

python/revng/model/v1/__init__.py

@@ -1,8 +1,12 @@
 #
 # This file is distributed under the MIT License. See LICENSE.md for details.
 #
+from typing import IO, Text, Union
+
+import yaml
 
 from ._generated import *
+from .base import YamlLoader, YamlDumper
 from .metaaddress import MetaAddress, MetaAddressType
 from .reference import Reference
 from .._common.monkeypatches import (
@@ -55,3 +59,7 @@ hashable_types = [
 
 for t, attr_name in hashable_types:
     make_hashable_using_attribute(t, attr_name)
+
+
+def load_model(stream: Union[bytes, IO[bytes], Text, IO[Text]]):
+    return yaml.load(stream, Loader=YamlLoader)

python/revng/model/v1/base.py

@@ -12,4 +12,9 @@ _substitutions = {
 
 MonkeyPatchingBaseClass = get_monkey_patching_base_class(
     _substitutions,
+    register_global_yaml_helpers=False,
 )
+YamlDumper = MonkeyPatchingBaseClass.YamlDumper
+YamlLoader = MonkeyPatchingBaseClass.YamlLoader
+# Allows to deserialize a model YAML to a Binary object using yaml.load(stream, Loader=YamlLoader)
+YamlLoader.add_path_resolver("!Binary", [])